*Demonstration of pollutant composition of ‘average’ stormwater PollutantAcute CriteriaStormwater* Copper (ppb)3.6 to 125 to 150 Lead (ppb)14 to 6520 to 200 Zinc (ppb)36 to to 600 Iron (ppb)1,0001,000 to 10,000 Chromium (ppb)4 to 1610 to 200 TPH (ppm)10^e1 to 15 Turbidity (units)10^g50 to 100 pH (units)6.5 to 95.5 to 8 Ammonia (ppm)13 to to 2 Nitrate (ppm)5 to 10% above background0.1 to 1 Introduction: Stormwater is a non-point source form of pollution. It is the result of impervious surfaces such as roads, roofs, parking lots, lawns, and any other surface not allowing rainwater to naturally filter into the ground. Water quickly collects and not having anywhere else to go, it heads downhill taking with it everything that has accumulated on the surface. Ecosystem services provided by wetlands (especially those containing detention ponds and swales) aid in reducing pollutants and improving water quality. Various natural processes such as sedimentation, absorption and filtration all help to remove contaminants from water. However this service alone is not enough to combat pollution entering water bodies. Therefore, effort needs to be taken to regulate the amount of pollution entering the system through stormwater. Discussion and Conclusion: Many of the constituents of stormwater are toxic and pose a direct threat to wildlife and natural ecosystem processes. Such pollutants are diverse in origin, vary greatly in concentration, and are difficult to pinpoint. The results show they could be anything from heavy metals found or rooftops, to oils on the road, to bacteria, or soil and sediments stripped from the ground. In order to examine the water quality of a system, it is important to understand the pollutant load entering it, as well as the natural processes taking place within it. Knowing what to test for and being able to identify possible sources is critical if any remediation efforts are to be made. The data presented here can be used to design water sampling protocols and steer further studies. Resources: Minton, Gary. Stormwater Treatment: Biological, Chemical, and Engineering Principles. Resource Planning Associates, Muthukrishnan, Swarna (2006). "Treatment Of Heavy Metals In Stormwater Runoff Using Wet Pond And Wetland Mesocosms," Proceedings of the Annual International Conference on Soils, Sediments, Water and Energy: Vol. 11, Article 9. Engstrom, Amy M (2004). Characterizing Water Quality of Urban Stormwater Runoff: Interactions of Heavy Metals and Solids in Seattle Residential Catchments. Master of Science in Civil Engineering Dissertation, University of Washington. Lake Superior Streams. Water Quality Impacts King County. The Science of Stormwater Images of Elements Coliscan Easygel Image Stormdrain Image Abstract: Stormwater runoff in urban areas is recognized as a major contributor to water pollution. Common contaminants include heavy metals, petroleum hydrocarbons, soils and other particles, and bacteria. Many of these are toxic, and all of them pose a concern to urban streams and the waters they feed. Pollutant load depends on many different factors. The goal of this project was to gain a better understanding of the content of stormwater. The results identify and quantify various pollutants. While natural wetlands are effective in sustaining water quality to a certain extent, this study shows that a thorough understanding of site specific pollutants is necessary to make any conclusions. Heavy Meatls: Copper, Zinc, Lead, Chromium, and many other metals end up in stormwater either dissolved, as particles, or attached to other solids. Different metals tend to be present in varying amounts either as dissolved or particle bound. Why it is important: Heavy metals are of great interest in stormwater because of their toxicity and the fact that unlike organic matter, they can not be destroyed. Metals bound to small enough particles may not be retained by sedimentation and flushed all the way into receiving bodies of water. Caused by: Stormwater runoff from impervious surfaces such as roadways, parking lots and roofs. Zinc is released by the wearing of automobile tires. Copper is found in automobile brake pads and released in brake dust. Turbidity: Measurement of how clear the water is. The greater the turbidity, the more solids there are suspended in the water. Solids can be organic, inorganic, chemical, or biological in nature. Any solids which are not able to fit through a specific size filter are considered dissolved. Why it is important: Organic contaminants, heavy metals, and nutrients can cling to the suspended solids through a process called absorption. Caused by: Erosion of soil, collection of particulate matter by stormwater, and stream bank disturbances. Bacteria: Bacteria originating from human and animal feces such as E. Coli and Fecal Coliform. Why it is important: Number one cause of water-borne illness. Outbreaks of fecal coloform bacteria are often responsible for closing beaches and preventing recreation. Bacteria such as fecal coliform and anterococci were found to be present in higher levels in urban watersheds. Caused by: Pet waste, sewer overflow after heavy rain, stormwater runoff. Nutrients: Ammonia, Nitrite, Nitrate, and Phosphate are all nutrients that play an important part of a wetland ecosystem and are required for plant and bacterial life. They represent part of the natural cycles taking placeHigh levels of nutrients possibly introduced through stormwater can cause problems such as unwanted algae growth. Results: Common Measures of Stormwater Quality Petroleum Hydrocarbons: Composed of carbon and hydrogen, they are a large family of compounds tracing their origin to crude oil. These include engine oils, gasoline, heating oils, and other petroleum based fuel sources. Why it is important: Poisons fish, birds, amphibians, and other aquatic life. In addition to being a direct pollutant, motor oil often contains other contaminants such as heavy metals, PAHs and other organic toxins. Caused by: Motor oil leaking from engines, exhaust fumes, illegal dumping of used oils, and leeching from contaminated soils. Iron Copper Lead Chromium Zinc Petroleum Hydrocarbons Turbidity Bacteria